You're reading the explanation of the relationship between the stories in Four Square Less One, a collection of short stories by Trevor Hopkins (email).
Firstly, the arrangement of the fifteen stories reflects that well-known puzzle. I was amused to discover that this is sometimes known as a Mystic Square.
In this puzzle, fifteen tiles can be slid around in a frame, and the objective is to re-arrange then into the correct pattern: 1 to 15 in order, with the blank square in the bottom right-hand corner. When I was first thinking about these stories, I certainly spent quite a lot of time re-aranging the order to make this interesting pattern.
The Stories
The four columns in the square represent four different kinds of settings. From left to right, they are:
- British University and Academia
- Historical settings, including future histories
- Bridges, and their construction
- Amateur (Ham) Radio
Similarly, the four rows represent different topics or subject areas. From top to bottom:
- Alien creatures and UFOs
- Magic and the Occult
- Ghosts and the Supernatural
- Sustainability and the Green Agenda
So, for example, story 6 - The Desert and the Sea - is at the intersection of History and Magic - which I think summarises the background to the story quite nicely.
